CVE-2018-18445

En el kernel de Linux 4.14.x, 4.15.x, 4.16.x, 4.17.x y versiones 4.18.x anteriores a la 4.18.13, el cálculo incorrecto de enlaces numéricos en el verificador BPF permite accesos a la memoria fuera de límites debido a que adjust_scalar_min_max_vals en kernel/bpf/verifier.c gestiona de manera incorrecta los desplazamientos a la derecha de 32 bits.

A security flaw was found in the Linux kernel in the adjust_scalar_min_max_vals() function in kernel/bpf/verifier.c. A faulty computation of numeric bounds in the BPF verifier permits out-of-bounds memory accesses because this function mishandles 32-bit right shifts. A local unprivileged user cannot leverage this flaw, but as a privileged user ("root") this can lead to a system panic and a denial of service or other unspecified impact. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is unlikely.